Ok seeing as some of you are trying to submit customs into the wrong folders I will try to discribe for each one. If your image is rejected you are probablly trying to submit it to the wrong folder. And simple "hair redoes" of ponies that are produced at a factory are not accepted at all.
Custom Pony Drawings: This is the ONLY place for pony drawings. These drawings that have one or more NONE Hasbro ponies.
Custom Hasbro Ponies: G1 ponies done as G4's or remixes of existing Hasbro ponies
Realisic Customs: Custom Ponies that look like real horses
Holiday and Season Customs: Customs done for Christmas and seasons like summer ect...
Persona Custom: People's personal customs
Fairy Customs: Customs with Fairy wings or fairies as a cuite marks
Unicorn Customs: Custom Unicorns
...Ok I think you guys get the hint if you do have questions just send a message
Also

is offering trades take a look at the page
[link]